The objective of this Phase III clinical trial is to assess the safety and efficacy of the UVAR photopheresis system in conjunction with UVADEX (liquid 8-methoxypsoralen) in the treatment of the skin manifestations of patients with early onset progressive systemic sclerosis (PSS). This is a multicenter clinical trial which is randomized and double-blinded and has a control (placebo photopheresis) treatment arm. Each eligible patient with signed informed consent is admitted to the General Clinical Research Center once a month for thirteen, two-day treatments. To date, at the Stanford center, a total of 10 patients have been enrolled in the study. Two patients are currently enrolled, 3 have completed the study and 5 have withdrawn early. Four of these five patients withdrew because or lack of response or disease progression and the fifth patient withdrew due to the onset of a new medical illness which was considered not related to her PSS nor to her treatments. The efficacy results will be available when the last patients in all centers have completed the study. Summary of safety analysis will be available at the conclusion of the multicenter study. The study has achieved its necessary enrollment goal for statistical analysis, and thus has been closed to any new enrollment. There will be no new patient enrollment in any of the participating centers.